U.S. patent application number 15/157857 was filed with the patent office on 2017-11-23 for shaped cooling passages for turbine blade outer air seal.
The applicant listed for this patent is United Technologies Corporation. Invention is credited to Timothy M. Davis, Paul M. Lutjen, Kevin J. Ryan.
Application Number | 20170335706 15/157857 |
Document ID | / |
Family ID | 58715137 |
Filed Date | 2017-11-23 |
United States Patent
Application |
20170335706 |
Kind Code |
A1 |
Davis; Timothy M. ; et
al. |
November 23, 2017 |
SHAPED COOLING PASSAGES FOR TURBINE BLADE OUTER AIR SEAL
Abstract
A core assembly for fabricating an air cooled engine component
for a gas turbine engine includes an end portion for defining
passages within a side of an engine component. The end portion
defines a first cross-section. A middle portion is spaced apart
from the end portion and defines passages through a middle part of
the engine component. The middle portion defines a second
cross-section. One of the first cross-section and the second
cross-section includes a first height greater than a second height.
An air cooled engine component for a gas turbine engine and a gas
turbine engine are also disclosed.
Inventors: |
Davis; Timothy M.;
(Kennebunk, ME) ; Lutjen; Paul M.; (Kennebunkport,
ME) ; Ryan; Kevin J.; (Alfred, ME) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
United Technologies Corporation |
Farmington |
CT |
US |
|
|
Family ID: |
58715137 |
Appl. No.: |
15/157857 |
Filed: |
May 18, 2016 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F01D 25/12 20130101;
F05D 2240/11 20130101; F05D 2230/21 20130101; F05D 2240/35
20130101; F05D 2260/232 20130101; F02C 3/04 20130101; B22C 9/103
20130101; F05D 2220/32 20130101; F01D 5/06 20130101; F01D 11/08
20130101; Y02T 50/675 20130101 |
International
Class: |
F01D 11/08 20060101
F01D011/08; F02C 3/04 20060101 F02C003/04; F01D 5/06 20060101
F01D005/06; F01D 25/12 20060101 F01D025/12 |
Claims
1. A core assembly for fabricating an air cooled engine component
for a gas turbine engine, the core assembly comprising: an end
portion for defining passages within a side of an engine component,
the end portion defining a first cross-section; and a middle
portion spaced apart from the end portion and defining passages
through a middle part of the engine component, the middle portion
defining a second cross-section, wherein one of the first
cross-section and the second cross-section includes a first height
greater than a second height.
2. The core assembly as recited in claim 1, wherein the first
cross-section comprises the first height and the second
cross-section comprises the second height.
3. The core assembly as recited in claim 2, wherein the first
height is uniform across the first cross-section for a first width
and the second height is uniform across the second cross-section
for a second width.
4. The core assembly as recited in claim 2, including a transition
portion between the middle portion and the end portion, the
transition portion including a third cross-section including a
third height that is greater than the second height and less than
the first height.
5. The core assembly as recited in claim 4, wherein the middle
portion includes a middle length, the end portion includes an end
length and the transition portion includes a transition length with
the transition length being smaller than both the middle length and
the end length.
6. The core assembly as recited in claim 1, wherein the first
height is no more than twice as large as the second height.
7. The core assembly as recited in claim 3, wherein the end portion
comprises a first end portion and a second end portion and both the
first side portion and the second side portion define passages
including the first height and the first width.
8. The core assembly as recited in claim 7, wherein side portion
and the middle portion comprise a single unitary integral part for
forming continuous passages from the first end to the second
end.
9. The core assembly as recited in claim 1, wherein the first
cross-section includes a middle part disposed between a first side
and a second side, with each of the first side and the second side
being at the first height and the middle part being the second
height.
10. The core assembly as recited in claim 1, wherein the first
cross-section includes a middle part disposed between a first side
and a second side, with each of the first side and the second side
being at the second height and the middle part being the first
height.
11. The core assembly as recited in claim 1, wherein the first
cross-section includes a middle part disposed between a first side
and a second side, with the middle part being the first height and
tapering from the first height to the second height at each of the
first side and the second side.
12. An air cooled engine component for a gas turbine engine, the
engine component comprising: a first end; a second end; a middle
portion; and at least one passage extending from the first end
through the middle portion to the second end, the at least one
passage including a first cross-section within the first end and
the second end and a second cross-section within the middle
portion, wherein one of the first cross-section and the second
cross-section includes a first height greater than a second
height.
13. The engine component as recited in claim 12, wherein the first
cross-section comprises the first height and the second
cross-section comprises the second height.
14. The engine component as recited in claim 12, wherein the first
height is uniform across the first cross-section for a first width
and the second height is uniform across the second cross-section
for a second width.
15. The engine component as recited in claim 12, including a
transition portion between the middle portion and each of the first
end and the second end, the transition portion including a third
cross-section including a third height that is greater than the
second height and less than the first height.
16. The engine component as recited in claim 12, wherein the first
height is no more than twice as large as the second height.
17. The engine component as recited in claim 12, wherein the first
cross-section includes a middle part disposed between a first side
and a second side, with each of the first side and the second side
being at the first height and the middle part being the second
height.
18. The engine component as recited in claim 12, wherein the first
cross-section includes a middle part disposed between a first side
and a second side, with each of the first side and the second side
being at the second height and the middle part being the first
height.
19. The engine component as recited in claim 12, wherein the first
cross-section includes a middle part disposed between a first side
and a second side, with the middle part being the first height and
tapering from the first height to the second height at each of the
first side and the second side.
20. A gas turbine engine comprising; a compressor section; a
combustor receiving compressed air from the compressor section for
mixing with fuel to generate a high-energy exhaust gas flow; and a
turbine section receiving the high-energy exhaust gas flow from the
combustor for driving the compressor section, the turbine section
including a plurality of rotating stages and blade outer air seals
defining a portion of a gas flow path, the blade outer air seal
including first end, a second end, a middle portion, and at least
one passage extending from the first end through the middle portion
to the aft end, the at least one passage including a first
cross-section within the first end and the second end and a second
cross-section within the middle portion, wherein one of the first
cross-section and the second cross-section includes a first height
greater than a second height.
21. The gas turbine engine as recited in claim 20, wherein the
blade outer air seal includes a transition portion between the
middle portion and each of the first end and the second end, the
transition portion including a third cross-section including a
third height that is greater than the second height and less than
the first height and the first height is no more than twice as
large as the second height.
22. The gas turbine engine as recited in claim 20, wherein the
first cross-section includes a middle part disposed between a first
side a second side, with each of the first side and the second side
being at the first height and the middle part being the second
height.
Description
BACKGROUND
[0001] A gas turbine engine typically includes a fan section, a
compressor section, a combustor section and a turbine section. Air
entering the compressor section is compressed and delivered into
the combustion section where it is mixed with fuel and ignited to
generate a high-energy exhaust gas flow. The high-energy exhaust
gas flow expands through the turbine section to drive the
compressor and the fan section.
[0002] Various components are supported within a case to define a
gas path for the high-energy exhaust flow. Components within the
gas path are exposed to extremes of temperatures and pressures that
can exceed material capabilities. Accordingly, cooling air is
provided along surfaces of gas path components to maintain
temperatures within acceptable material capabilities.
[0003] One component within the gas path is a blade outer air seal
that is disposed adjacent to a rotating airfoil of within the
turbine section. The blade outer air seal defines a clearance
between the airfoil and the static structure of the engine. Cooling
passages defined within the blade outer air seal are formed
utilizing a core that is later removed. Cooling passages perform
best when relatively small such that thermal energy may be
efficiently transferred to the cooling fluid. However, the thinner
smaller passages require thinner smaller core cross-sections that
can be fragile and complicate manufacture.
SUMMARY
[0004] In a featured embodiment, a core assembly for fabricating an
air cooled engine component for a gas turbine engine includes an
end portion for defining passages within a side of an engine
component. The end portion defines a first cross-section. A middle
portion is spaced apart from the end portion and defines passages
through a middle part of the engine component. The middle portion
defines a second cross-section. One of the first cross-section and
the second cross-section includes a first height greater than a
second height.
[0005] In another embodiment according to the previous embodiment,
the first cross-section includes the first height and the second
cross-section includes the second height.
[0006] In another embodiment according to any of the previous
embodiments, the first height is uniform across the first
cross-section for a first width and the second height is uniform
across the second cross-section for a second width.
[0007] In another embodiment according to any of the previous
embodiments, includes a transition portion between the middle
portion and the end portion. The transition portion includes a
third cross-section including a third height that is greater than
the second height and less than the first height.
[0008] In another embodiment according to any of the previous
embodiments, the middle portion includes a middle length. The end
portion includes an end length and the transition portion includes
a transition length with the transition length being smaller than
both the middle length and the end length.
[0009] In another embodiment according to any of the previous
embodiments, the first height is no more than twice as large as the
second height.
[0010] In another embodiment according to any of the previous
embodiments, the end portion includes a first end portion and a
second end portion and both the first side portion and the second
side portion define passages including the first height and the
first width.
[0011] In another embodiment according to any of the previous
embodiments, side portion and the middle portion include a single
unitary integral part for forming continuous passages from the
first end to the second end.
[0012] In another embodiment according to any of the previous
embodiments, the first cross-section includes a middle part
disposed between a first side and a second side, with each of the
first side and the second side being at the first height and the
middle part being the second height.
[0013] In another embodiment according to any of the previous
embodiments, the first cross-section includes a middle part
disposed between a first side and a second side, with each of the
first side and the second side being at the second height and the
middle part being the first height.
[0014] In another embodiment according to any of the previous
embodiments, the first cross-section includes a middle part
disposed between a first side and a second side, with the middle
part being the first height and tapering from the first height to
the second height at each of the first side and the second
side.
[0015] In another featured embodiment, an air cooled engine
component for a gas turbine engine includes a first end, a second
end, a middle portion, and at least one passage extends from the
first end through the middle portion to the second end. The at
least one passage includes a first cross-section within the first
end and the second end and a second cross-section within the middle
portion. One of the first cross-section and the second
cross-section includes a first height greater than a second
height.
[0016] In another embodiment according to the previous embodiment,
the first cross-section includes the first height and the second
cross-section includes the second height.
[0017] In another embodiment according to any of the previous
embodiments, the first height is uniform across the first
cross-section for a first width and the second height is uniform
across the second cross-section for a second width.
[0018] In another embodiment according to any of the previous
embodiments, includes a transition portion between the middle
portion and each of the first end and the second end. The
transition portion includes a third cross-section including a third
height that is greater than the second height and less than the
first height.
[0019] In another embodiment according to any of the previous
embodiments, the first height is no more than twice as large as the
second height.
[0020] In another embodiment according to any of the previous
embodiments, the first cross-section includes a middle part
disposed between a first side and a second side, with each of the
first side and the second side being at the first height and the
middle part being the second height.
[0021] In another embodiment according to any of the previous
embodiments, the first cross-section includes a middle part
disposed between a first side and a second side, with each of the
first side and the second side being at the second height and the
middle part being the first height.
[0022] In another embodiment according to any of the previous
embodiments, the first cross-section includes a middle part
disposed between a first side and a second side, with the middle
part being the first height and tapering from the first height to
the second height at each of the first side and the second
side.
[0023] In another featured embodiment, a gas turbine engine
includes a compressor section. A combustor receives compressed air
from the compressor section for mixing with fuel to generate a
high-energy exhaust gas flow. A turbine section receives the
high-energy exhaust gas flow from the combustor for driving the
compressor section. The turbine section includes a plurality of
rotating stages and blade outer air seals defining a portion of a
gas flow path. The blade outer air seal includes a first end, a
second end, a middle portion, and at least one passage extending
from the first end through the middle portion to the aft end. The
at least one passage includes a first cross-section within the
first end and the second end and a second cross-section within the
middle portion. One of the first cross-section and the second
cross-section includes a first height greater than a second
height.
[0024] In another embodiment according to the previous embodiment,
the blade outer air seal includes a transition portion between the
middle portion and each of the first end and the second end. The
transition portion includes a third cross-section including a third
height that is greater than the second height and less than the
first height and the first height is no more than twice as large as
the second height.
[0025] In another embodiment according to any of the previous
embodiments, the first cross-section includes a middle part
disposed between a first side a second side, with each of the first
side and the second side being at the first height and the middle
part being the second height.
[0026] Although the different examples have the specific components
shown in the illustrations, embodiments of this disclosure are not
limited to those particular combinations. It is possible to use
some of the components or features from one of the examples in
combination with features or components from another one of the
examples.
[0027] These and other features disclosed herein can be best
understood from the following specification and drawings, the
following of which is a brief description.
BRIEF DESCRIPTION OF THE DRAWINGS
[0028] FIG. 1 is a schematic view of an example gas turbine engine
embodiment.
[0029] FIG. 2 is a schematic view of a portion of a turbine
section.
[0030] FIG. 3 is a schematic view of a core for defining passages
within a blade outer air seal.
[0031] FIG. 4 is a schematic view of an example core for defining
features within a blade outer air assembly.
[0032] FIG. 5 is a schematic view of a passage cross-section
embodiment.
[0033] FIG. 6 is a schematic of another passage cross-section
embodiment.
[0034] FIG. 7 is a schematic view of another core defining passages
within a blade outer air seal.
[0035] FIG. 8 is a schematic view of an air passage cross-section
embodiment.
[0036] FIG. 9 is a cross-section of another example air passage
embodiment.
[0037] FIG. 10 is yet another cross-section of an example air
passage embodiment.
DETAILED DESCRIPTION
[0038] FIG. 1 schematically illustrates an example gas turbine
engine 20 that includes a fan section 22, a compressor section 24,
a combustor section 26 and a turbine section 28. Alternative
engines might include an augmenter section (not shown) among other
systems or features. The fan section 22 drives air along a bypass
flow path B while the compressor section 24 draws air in along a
core flow path C where air is compressed and communicated to a
combustor section 26. In the combustor section 26, air is mixed
with fuel and ignited to generate a high pressure exhaust gas
stream that expands through the turbine section 28 where energy is
extracted and utilized to drive the fan section 22 and the
compressor section 24.
[0039] Although the disclosed non-limiting embodiment depicts a
two-spool turbofan gas turbine engine, it should be understood that
the concepts described herein are not limited to use with two-spool
turbofans as the teachings may be applied to other types of turbine
engines; for example a turbine engine including a three-spool
architecture in which three spools concentrically rotate about a
common axis and where a low spool enables a low pressure turbine to
drive a fan via a gearbox, an intermediate spool that enables an
intermediate pressure turbine to drive a first compressor of the
compressor section, and a high spool that enables a high pressure
turbine to drive a high pressure compressor of the compressor
section.
[0040] The example engine 20 generally includes a low speed spool
30 and a high speed spool 32 mounted for rotation about an engine
central longitudinal axis A relative to an engine static structure
36 via several bearing systems 38. It should be understood that
various bearing systems 38 at various locations may alternatively
or additionally be provided.
[0041] The low speed spool 30 generally includes an inner shaft 40
that connects a fan 42 and a low pressure (or first) compressor
section 44 to a low pressure (or first) turbine section 46. The
inner shaft 40 drives the fan 42 through a speed change device,
such as a geared architecture 48, to drive the fan 42 at a lower
speed than the low speed spool 30. The high-speed spool 32 includes
an outer shaft 50 that interconnects a high pressure (or second)
compressor section 52 and a high pressure (or second) turbine
section 54. The inner shaft 40 and the outer shaft 50 are
concentric and rotate via the bearing systems 38 about the engine
central longitudinal axis A.
[0042] A combustor 56 is arranged between the high pressure
compressor 52 and the high pressure turbine 54. In one example, the
high pressure turbine 54 includes at least two stages to provide a
double stage high pressure turbine 54. In another example, the high
pressure turbine 54 includes only a single stage. As used herein, a
"high pressure" compressor or turbine experiences a higher pressure
than a corresponding "low pressure" compressor or turbine.
[0043] The example low pressure turbine 46 has a pressure ratio
that is greater than about 5. The pressure ratio of the example low
pressure turbine 46 is measured prior to an inlet of the low
pressure turbine 46 as related to the pressure measured at the
outlet of the low pressure turbine 46 prior to an exhaust
nozzle.
[0044] A mid-turbine frame 58 of the engine static structure 36 is
arranged generally between the high pressure turbine 54 and the low
pressure turbine 46. The mid-turbine frame 58 further supports
bearing systems 38 in the turbine section 28 as well as setting
airflow entering the low pressure turbine 46.
[0045] Airflow through the core airflow path C is compressed by the
low pressure compressor 44 then by the high pressure compressor 52
mixed with fuel and ignited in the combustor 56 to produce high
energy exhaust gases that are then expanded through the high
pressure turbine 54 and low pressure turbine 46. The mid-turbine
frame 58 includes vanes 60, which are in the core airflow path and
function as an inlet guide vane for the low pressure turbine 46.
Utilizing the vane 60 of the mid-turbine frame 58 as the inlet
guide vane for low pressure turbine 46 decreases the length of the
low pressure turbine 46 without increasing the axial length of the
mid-turbine frame 58. Reducing or eliminating the number of vanes
in the low pressure turbine 46 shortens the axial length of the
turbine section 28. Thus, the compactness of the gas turbine engine
20 is increased and a higher power density may be achieved.
[0046] The disclosed gas turbine engine 20 in one example is a
high-bypass geared aircraft engine. In a further example, the gas
turbine engine 20 includes a bypass ratio greater than about six
(6), with an example embodiment being greater than about ten (10).
The example geared architecture 48 is an epicyclical gear train,
such as a planetary gear system, star gear system or other known
gear system, with a gear reduction ratio of greater than about
2.3.
[0047] In one disclosed embodiment, the gas turbine engine 20
includes a bypass ratio greater than about ten (10:1) and the fan
diameter is significantly larger than an outer diameter of the low
pressure compressor 44. It should be understood, however, that the
above parameters are only exemplary of one embodiment of a gas
turbine engine including a geared architecture and that the present
disclosure is applicable to other gas turbine engines.
[0048] A significant amount of thrust is provided by the bypass
flow B due to the high bypass ratio. The fan section 22 of the
engine 20 is designed for a particular flight condition--typically
cruise at about 0.8 Mach and about 35,000 feet. The flight
condition of 0.8 Mach and 35,000 ft., with the engine at its best
fuel consumption--also known as "bucket cruise Thrust Specific Fuel
Consumption (`TSFC`)"--is the industry standard parameter of
pound-mass (lbm) of fuel per hour being burned divided by
pound-force (lbf) of thrust the engine produces at that minimum
point.
[0049] "Low fan pressure ratio" is the pressure ratio across the
fan blade alone, without a Fan Exit Guide Vane ("FEGV") system. The
low fan pressure ratio as disclosed herein according to one
non-limiting embodiment is less than about 1.50. In another
non-limiting embodiment the low fan pressure ratio is less than
about 1.45.
[0050] "Low corrected fan tip speed" is the actual fan tip speed in
ft/sec divided by an industry standard temperature correction of
[(Tram.degree. R)/(518.7.degree. R)].sup.0.5. The "Low corrected
fan tip speed", as disclosed herein according to one non-limiting
embodiment, is less than about 1150 ft/second.
[0051] The example gas turbine engine includes the fan 42 that
comprises in one non-limiting embodiment less than about 26 fan
blades. In another non-limiting embodiment, the fan section 22
includes less than about 20 fan blades. Moreover, in one disclosed
embodiment the low pressure turbine 46 includes no more than about
6 turbine rotors schematically indicated at 34. In another
non-limiting example embodiment the low pressure turbine 46
includes about 3 turbine rotors. A ratio between the number of fan
blades 42 and the number of low pressure turbine rotors is between
about 3.3 and about 8.6. The example low pressure turbine 46
provides the driving power to rotate the fan section 22 and
therefore the relationship between the number of turbine rotors 34
in the low pressure turbine 46 and the number of blades 42 in the
fan section 22 disclose an example gas turbine engine 20 with
increased power transfer efficiency.
[0052] Referring to FIG. 2 with continued reference to FIG. 1, a
blade outer air seal (BOAS) 62 defines a portion of the core flow
path C for the high-energy exhaust gasses generated in the
combustor 56. The BOAS 62 is disposed radially outward of a
rotating airfoil 64. The BOAS 62 includes passages 70 that receive
cooling air utilized to maintain the gas path surface at a
temperature within material capabilities. The BOAS 62 includes a
forward side 66 and an aft side 68. Each of the BOAS 62 are
disposed within channels defined within a static structure 36 of
the turbine engine 20. The BOAS 62 are supported within the static
structure 36 and circumferentially surround rotatable airfoils 64
of the turbine section 28.
[0053] Referring to FIG. 3 with continued reference to FIG. 2, each
of the BOAS 62 includes the air passages 70 for cooling air flow.
The passages 70 are formed using a sacrificial core schematically
indicated at 72. FIG. 3 illustrates the blade outer air seal 62
perimeter outline relative to the core 72. The core 72 is of a
material that may be over molded with the metal alloy utilized to
construct and form the BOAS 62 while being able to be removed once
the BOAS 62 is completely formed. This disclosure contemplates use
of the disclosed core 72 with any variation of known lost core
molding processes.
[0054] As with all lost core molding processes, the core 72 defines
empty spaces within the interior sections of a completed BOAS 62.
Similarly, open spaces in the core 72 define rigid and solid
structures of the completed BOAS 62. In this example, the core 72
includes an open section 98 that is utilized to form a solid rib or
wall portion within an interior space of the completed BOAS 62. The
structure of the BOAS 62 is therefore dependent on the structure of
the core 72 and both the completed BOAS 62 and the core 72 are
within the contemplation of this disclosure.
[0055] Accordingly, the core 72 defines air passages extending
through the BOAS 62. Smaller airflow passages provide better
thermal transfer as compared to larger airflow passages and
therefore it is desirable to provide the core 72 with a small
cross-sectional area to define smaller air flow passages through
the BOAS 62. Smaller cross-sections, however may make certain core
sections fragile and difficult to handle during manufacturing.
Moreover, thinner core sections 72 complicate manufacturing and can
result in undesirable defects within the finished blade outer air
seal 62.
[0056] The example core 72 includes features that define air
passages to improve thermal transfer while also improving
manufacturability by tailoring cross-sectional areas and shapes in
areas particularly susceptible to damage during manufacturing.
[0057] Referring to FIGS. 4, 5 and 6, an example core 72 is shown
that defines air passages through a BOAS 62 and includes an open
section 98. The open section 98 defines a solid rib in the
completed BOAS 62. The core 72 includes middle portion 82 between a
first end portion 80a and a second end portion 80b. A transition
portion 84 is disposed between the middle portion 82 and each of
the end portions 80a and 80b. The end portions 80a, 80b, middle
portion 82 and transition portions 84 refer to features in the core
72. Accordingly, the example core 72 includes a non-uniform shape
from the first end portion 80a to the second end portion 80b.
[0058] The features of the core 72 correspond to portions of
completed passages in the completed BOAS 62. In the BOAS 62, each
of the airflow passages 70 (FIG. 2) includes end portions 74A, 74B,
transition portions 78 and middle portions 76. The airflow passages
70 are continuous from one end portion 74A to the other end portion
74B.
[0059] The core 72 defines the features of the passages 70 and
include a first passage cross-section 86. The first passage cross
section 86 defines the cross-section at the end portions 80b and
80a. The first passage cross-section 86 includes a first height 90
and a first width 96. A second passage cross-section 88 defines the
core 72 within the middle portion 82. The second passage
cross-section 88 includes a height 94 and a width 92. The first
passage cross-section 86 and the second passage cross-section 88
refer to portions of the core 72 that define the completed passages
and open areas.
[0060] The core portion that defines the first passage
cross-section 86 includes the first height 90 which is larger than
the second height 94 of the second passage cross section 88. In one
example embodiment, the first height 90 is two times greater than
the second height 94. In another example embodiment, the first
height 90 is no more than two times the second height 94.
Accordingly, the end portions 80a and 80b include a larger core
cross-section and thereby forms a larger completed air passage
within end portions 74A, 74B in the completed BOAS 62.
[0061] The transition area portion 84 of the core 72 includes a
passage cross-section that transitions between the second cross
section 88 of the middle portion 82 to the larger first
cross-sections 86 at the end portions 80a and 80b. The variable
height of the passages enable the use of thicker core sections in
areas most susceptible to damage during manufacturing. The thinner
second passage cross-section 88 defined by the core 72 in areas not
as susceptible to damage during manufacture. The resulting air
passage cross-section in the middle portion 76 of the completed
BOAS 62 therefore benefits from the improved thermal transfer
properties provided by the smaller cross-section.
[0062] Referring to FIG. 7, another core assembly 102 is
schematically illustrated for forming passages within a completed
BOAS 100. The example BOAS 100 is shown schematically by the dashed
line and includes passages that are formed by the core 102. In this
example, the core 102 includes a uniform shape and configuration
from a first end portion 130a to a second end portion 130b. The
cross-section of the core 102 includes a unique shape that improves
manufacturability while maintaining configurations desirable for
air passages in a completed BOAS 100.
[0063] In each of the disclosed example passage cross-sections, the
hot side, also referred to as the flow path side of the passage
wall of the BOAS 100 is the side that is down in the Figures.
[0064] Referring to FIG. 8 with continued reference to FIG. 7, a
first passage cross section 104 includes a middle section 112
between a first side section 110a and a second side section 110b.
The middle section 112 includes a height 128 and the side sections
110a and 110b includes a height 126. In this example, the height
126 at each of the side sections 110a and 110b is greater than the
height 128 of the middle sections. The end sections 110a and 110b
define ribs that provide increased strength to that part of the
core 102 during manufacture. The middle section 112 includes the
smaller height 128 of the core 102 that is strengthened at the end
sections 110a and 110b. Accordingly, the cross-section 104 of the
core 102 can have ribs that provide strengthening features to
enable more robust manufacturability while also maintaining the
smaller cross sectional area in the middle section 112 that
provides the desired thermal transfer properties in the completed
BOAS 100.
[0065] In this example, the ribs defined at the end sections 110a
and 110b extend on a side that is not exposed to flow path side of
the BOAS 100. In other words, the ribs of the end sections 110a and
110b extend from a side opposite the flow path or hot side of the
BOAS and the side of the passage that is uniform or flat as shown
in FIG. 8 is on the flow path side.
[0066] In this example the height 126 is no more than two (2) times
the height 128 of the middle section 112. In another disclosed
example embodiment, the height 126 is two (2) times the height 128
of the middle section 112.
[0067] Referring to FIG. 9, another passage cross section 106
includes the middle section 112 with a height 114 and the side
sections 110a and 110b with a height 116. In this example, the
middle section 112 includes the greater height 114 while the end
sections 110a and 110b include a reduced height. The height 114 of
the middle section 112 in one example embodiment is no more than
two (2) times the height 116 of the end sections 110a and 110b. In
another example embodiment the height of the middle section 112 is
two (2) times the height 116 at the end sections 110a and 110b. In
this example cross-section 106, the center middle section 112 with
the increased height 114 faces away from the hot side, or flow path
side of the BOAS, and the side opposite is nearest the flow path
side of the BOAS.
[0068] Referring to FIG. 10, another passage cross section 108
includes a middle section 118 with a height 124. Each end section
132A, 132B includes a height 120 that is smaller than the height
124. A transition region 122 is disposed between the middle section
118 and the end sections 132A, 132B such that a smooth transition
from the height 124 to the height 120 is provided by the core 102.
In one example embodiment, the height 124 is no more than two (2)
times the height 120 at the end sections 132A and 132b. In another
example embodiment, the height 120 is two (2) times the height 120
at the end sections 132A and 132B. Again, in this example the
middle portion 118 increased height is provided in a direction away
from the flow path side, such that the passage defines a uniform
straight surface on the flow path side.
[0069] Accordingly, the variable cross sections of the example core
provide improved strength and durability to improve and ease
manufacturing while maintaining the desired thermal transfer
properties for the completed BOAS. Moreover, while the example core
is disclosed by way of example for a BOAS, other structures that
include passages formed using a core would benefit from this
disclosure and are within the contemplation of this disclosure.
[0070] Although an example embodiment has been disclosed, a worker
of ordinary skill in this art would recognize that certain
modifications would come within the scope of this disclosure. For
that reason, the following claims should be studied to determine
the scope and content of this disclosure.
* * * * *